This is a follow-up issue of

ESFJ-107: Allow issue transition on board by column statusesDone

Description:

Scrolling while dragging is not supported by Dragula.js, therefore ESJF-107 introduced a script that allows to scroll while dragging an issue, but it requires weird “pushing” mouse movement to work.

We should consider changing how this works to eliminate need of scrolling at all. This can be achieved with substituting status areas with about 200px high “drop-zones” when the issue is dragged, so it can be easily placed in the desired status. This solution is very similar to how Jira handles it.

A/C:

• Dragging issue hides issues in columns and instead “drop areas” are shown.

• Remove “scroller” from board.ftl script.